The Psycho Sniper took a second weekend in a row off from his murderous rampage, suggesting that he may have a Saturday-Sunday job, is lying low or is scouting locations for more attacks, police said yesterday.

Like last weekend, Washington, D.C., and surrounding counties had a break from the random attacks, although police had a major presence on the streets, prepared to rush to any shooting.

Cops don’t know for sure why the killer suspended his spree for the second straight weekend, but they fear he’ll resume business as usual today, as he did last Monday, with the serious wounding of a 13-year-old boy.

One day after investigators briefly detained a man who fit a vague description of the sniper, Montgomery County Police Chief Charles Moose refused to say if cops are working on a composite sketch of the gunman.

Moose told “Fox News Sunday” that possible witnesses might see a sketch on TV and “mix that up with reality.”

“The concern is that we [would] pollute the whole thought process,” he said.

Police have asked the Defense Department to check various armed forces’ sniper schools for information about former students, rejected applicants or students kicked out for psychological problems, sources said.

The military-training angle is being eyed because investigators increasingly believe that the rampaging rifleman is more skilled at marksmanship than previously believed, police sources told The Post.

Investigators also are searching for clues to the killer’s identity in the subculture of “sniper wannabes,” who exchange information about weapons, ammunition and tactics associated with long-range shooting, police said. And they also are looking at people who have been rejected from police jobs.

Sniper-culture aficionados and criminal profilers earlier said that the Beltway sniper – who has killed eight and wounded two – needed to be merely a competent marksman to have felled his victims with a single, high-powered shot from a range of 150 yards or more.

But last Wednesday’s killing of Dean Meyers, 53, at a Virginia gas station changed that view among some investigators. In what was considered to be a very difficult shot, Meyers was hit in the head by a bullet that threaded a tight corridor between two fuel-pump islands after it was fired from more than 150 yards away.

That killing has investigators believing that the gunman is a trained sniper who is methodically planning his attacks in response to police tactics.

“He – or they – is very self-controlled and disciplined. He is clearly taking a lot of time and care into planning his next moves,” said one police source.

That source also said the sniper cares less about who his victims are and more about playing “cat and mouse” with police.

Cops weighed the idea of sending the killer some kind of message asking him to stop his two-week rampage. But they rejected that plan after concluding that the sniper would enjoy the idea of having power over them.

And they are being careful about what they say publicly, having been shaken last week when the gunman – apparently reacting to their claims that schools would be safe for children – shot the boy as he walked to a Bowie, Md., school.

Police yesterday staked out major intersections near highways, and frequently pulled over and checked white trucks resembling the ones seen around the sniper’s attacks.